We present Learn OCaml, a Web application that packs a set of learning activities for people who want to learn OCaml. It includes an integrated and reworked version of the venerable Try OCaml, and an exercise environment with automated grading derived from the one developed for the OCaml MOOC. It works entirely in the browser, the server being used for storing static files and synchronizing between different devices. A special effort has been made to make it usable on tablets, and even mobiles. A main public instance will be hosted at OCamlPro, but the project is open-source, and universities can host their own version on site. We will also provide a public repository for teachers to contribute lessons and exercises. A demo is currently hosted at: http://try.ocamlpro.com/learn-ocaml-demo. The source code is available as free software at: https://github.com/ocamlpro/learn-ocaml.